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"Harry Andreas" wrote in message ... In article , wrote: WaltBJ wrote: Having used an IRSTS in the F102A for over a year and a half (and teaching its use to other pilots) I am continually amazed at the refusal of the USAF and USN to employ some form of IRSTS in their fighters. Walt, the F-14 has had an IRSTS since the earlyt '80s, and the F-14D had both IRSTS and TCS. Modern FLIR pods can also do double duty as IRSTS, albeit they usually will be cued by radar. As simple and crude as the Deuce's IR system was, it still added a whole new spectrum of attack modes to the weapons system. Undetectable, unjammable, good against fighters in the weeds, line of sight detection against head-on B58s at M 2.0 and picking up afterburning 106s at 40 miles head-on. Surely a 21st century IRSTS would be far superior to what we enjoyed back in the 60's. And the Deuce's system weighed less than 50 pounds all told . . . the powers that be might ask themselves why the Russians have IRSTS on all their fighters. Part of the reason is that they were designed to operate under tight GCI, and their a/c radars were/are generally much inferior to US systems as far as performance goes. So, the ability to be vectored by GCI within range and then use a passive system for acquisition/tracking instead of letting the opposing pilots know their general direction (by RWR) where they're coming from,which allows the other side to radar search for them long before they reach their own detection range, probably plays a big part. As long as we feel we have the BVR range advantage, we don't want to close to IR missile range. In the case of the F-22 and even more the F-35, both of them will be getting a lot of their info from off-board sensors, as well passive sensors (the F-35 will have two internal FLIRS, one forward and the other downward-looking). And then there's always the money issue, which Kevin mentioned -- with the F-22 costs spiraling out of sight, I imagine they looked to cut the 'nice to have' stuff to try and keep the cost reasonable [Sic.] and make sure it gets into production, after which they can then load it up with all the goodies as retrofits. The IRST was deleted at program inception, long before the costs spiralled out of control. The reason? Cost. They knew well from experience that the cost of the hardware, cost of the software, and cost of integration and flight test were going to be too high to support it's functionality. I can only imagine how bad it would be now if they had decided to keep it. (BTW, I worked the ATF program and early parts of F-22) At inception? I thought the decision to axe the IRST came well into the nineties? The folks at Arnold were doing wind model testing of LMCO's AIRST as mounted in the then-F-22 as late as 96-97 (see: http://www.arnold.af.mil/aedc/testhi.../trisonics.pdf ). And the AFA noted it was still being developed in 97 as well (www.afa.org/magazine/nov1997/1197airborn.asp). Brooks -- Harry Andreas Engineering raconteur |
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phil hunt wrote:
On Sun, 29 Aug 2004 22:11:54 -0400, Kevin Brooks wrote: The F-22 was to have an IRST, but it was subsequently deleted from the program. Do you happen to know why? Probably because every IR search-and-track mechanism ever made has failed to be worth its cost. (Very short range, complicated electronics, sometimes- dunious operation.) |
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"Dweezil Dwarftosser" wrote in message ... phil hunt wrote: On Sun, 29 Aug 2004 22:11:54 -0400, Kevin Brooks wrote: The F-22 was to have an IRST, but it was subsequently deleted from the program. Do you happen to know why? Probably because every IR search-and-track mechanism ever made has failed to be worth its cost. (Very short range, complicated electronics, sometimes- dunious operation.) The LMCO AIRST destined (at one time) for the F-22 is based upon the IRST used in the F-14, which from what I have read is not a very bad system. Cost was the major reason AIRST was dumped. Brooks |
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Yes, I understand all that - but I maintain today, as I have in the
past, that it will not be long before turning on a radar set will be tantamount to suicide. And, yes, I know about LPI radars. But the one thing about a long-range radar is that it has to radiate power, and one side can detect the other's transmitter long before they themselves are detected. Now add space elint to the equation, GPS/Inertial guided missiles with ecm terminal homing and blithely boring holes with the radar on will quickly go out of fashion. Even more so, radar ground sites in known/easily pin-pointed stations. Boats, too, for that matter. Might as well have a huge neon sign saying "Hit me". Even in 1960 we had missiles that could switch to ecm home; not much of a step to homing on AI radar with our progress in micro processors. Now bring in satellite elint and direction . . . Walt BJ |
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"WaltBJ" wrote Yes, I understand all that - but I maintain today, as I have in the past, that it will not be long before turning on a radar set will be tantamount to suicide. And, yes, I know about LPI radars. But the one thing about a long-range radar is that it has to radiate power, and one side can detect the other's transmitter long before they themselves are detected. Now add space elint to the equation, GPS/Inertial guided missiles with ecm terminal homing and blithely boring holes with the radar on will quickly go out of fashion. Even more so, radar ground sites in known/easily pin-pointed stations. Boats, too, for that matter. Might as well have a huge neon sign saying "Hit me". Even in 1960 we had missiles that could switch to ecm home; not much of a step to homing on AI radar with our progress in micro processors. Now bring in satellite elint and direction . . . Fortunately, F22s or F35s in operation won't do that. Both aircraft have intraflight datalinks for cross-linking data among aircraft as well as other links for e.g. downloading the take from RJs and satellite sensors. The IFDLs allow a flight of F22s to share the radar duty cycle across multiple aircraft in whatever strategy most suits the occasion, meaning that any ESM location data on a particular emitter ages fast, especially if it's cruising at M1.5. All the GPS in the world does you no good if you lose location awareness on the target . As an aside, F35s will have not two but seven IR cameras. The FLIR EOTS sensor is augmented by a six-camera Distributed Aperature System of IR sensors that gives the pilot a 4pi steradian field of view, including places where aircraft structure gets in the way. |
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On 3 Sep 2004 20:03:42 -0700, WaltBJ wrote:
Yes, I understand all that - but I maintain today, as I have in the past, that it will not be long before turning on a radar set will be tantamount to suicide. And, yes, I know about LPI radars. But the one thing about a long-range radar is that it has to radiate power, and one side can detect the other's transmitter long before they themselves are detected. The strength of the signal at the illuminated aircraft is much stronger than the echo that gets back to the transmitting aircraft -- a million time or more stronger. If there are grond stations that have passive detectors, these detectors won't be limited by the size and mass constrainsts of ones in aircraft, and will liekly have an even better chance of picking up a signal (and of course of sending the details to other units on their side). For this reason, I think passive sensors will become increasingly important compared to active sensors. Now add space elint to the equation, GPS/Inertial guided missiles with ecm terminal homing and blithely boring holes with the radar on will quickly go out of fashion. Even more so, radar ground sites in known/easily pin-pointed stations. Certainly. Aircraft are hard to hit, even once detected, because they travel very fast. Ships and ground stations are much less mobile. -- "It's easier to find people online who openly support the KKK than people who openly support the RIAA" -- comment on Wikipedia (Email: zen19725 at zen dot co dot uk) |
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